Computers and/or other data processing systems are increasingly used to compose, process or modify music in the form of digital audio data. Digital audio processing software is e.g. available from APPLE Inc. under the product names GarageBand (for home use) and LogicPro (for professional use). Such Digital Audio Workstations (DAW) or systems allow the user to build a piece of music, by arranging and editing self-recorded and pre-fabricated music building blocks on so called tracks, each track representing a certain instrument or sound. The tracks can be visualized on a graphical user interface of the DAW.
A known system available from the Steinberg company under the product name Cubase 4 further allows a user to manipulate selectable parts of a song (including all its tracks) by displaying lists of such parts wherein these parts can be re-arranged for playback in a different order.
However, handling of such lists is cumbersome for the users and the result of the manipulation can only be assessed after playing back the modified digital audio data. There is no immediate feedback to the user while he is manipulating the parts of the piece of music.